Patent GB-440650-A (GB)
Title: An improved transmission gear
IPC: F16D67/00
Filed: 1934-06-29
Abstract: 440,650. Hydro-mechanical variablespeed gearing. YOXALL, J., York House, Deganwy, Carnarvonshire. June 29, 1934, No. 19278. [Class 80 (ii)] Variable-speed transmission gearing suitable for vehicles comprises in combination an hydraulic coupling or fluid flywheel 5, 9, Fig. 1, a series of compounded epicyclic trains A, B C, and manually-operated hydraulic means 41 for selectively controlling the speed ratio. The outer hydraulic member 5 is fast on the engine shaft 6 and is connected through a two-part sleeve 16 to a female clutch cone 31. The hydraulic coupling which uses oil may be as described in Specification 414,641, [Group XXIX]. The driven hydraulic member 9 is fast on a sleeve 13 connected through a one-way roller clutch 23 to a main shaft 21 to which are secured sun-gears 48, 51 of the first two epicyclic trains A, B. The one-way clutch 23 may be locked solid at will by a dog clutch 19 operated through carbon rings 26 from a fork 18. A male clutch cone 32 slides on a sleeve connected to the annulus 33 of the train A. When the cone clutch is engaged, the drive is shared between the hydraulic members 5, 9 which are drivingly connected independently to different elements 33, 48 of the train A. This yields third or top speed. For first speed a brake 58 is applied to the annulus 49 of the train B. The sun 51 drives and the planet carrier 50, which is fast on a driven shaft 52, is driven at reduced speed. For second speed, a brake 56 is applied to the annulus 33 of the train A. The sun 48 driving causes the carrier 47 to turn forwards carrying with it the annulus 49 of the train B so that there is an added speed to the carrier 50 of that train. When the annulus 53 of the train C is held by a brake 60, trains B and C are operative together to effect a reversed drive. The clutch 32 and brakes 56, 58, 60 are put into action selectively by admitting pressure oil to cylinders 39, 62, 163, and 64, respectively, which is effected by turning a selector valve 41 from a rod 43 which is carried by connections up the steering column and which forms the sole and independent manual control of the variable-speed gearing. Oil is supplied to the valve 41 by a pump driven from an eccentric 45 which is driven by the engine. A preferred form of pump is described with reference to Fig. 2 (not shown), which forms the subject-matter of Specification 440,686, [Group XXVIII]. A lever 46 oscillates up and down between spring pivots 86 and transversely so that its lower end 87 moves pistons in two pumps 92 opposite one another. When a selected gear-operating cylinder such as 64 has taken all the pumped oil required, the spring pivots 86 yield idly and the pumping is reduced to capacity for supplying oil for lubrication only. The clutch 32 is operated by a cam ring 38 which is turned against balls 37 through a suitable crank from a piston in the cylinder 39. Each of the brakes is preferably in two parts such as 60, 61, Fig. 3, side by side. Oil passing from the rotary selector valve 41 enters the cylinder such as 64 between two pistons 106, 107 which are thrust apart in a balanced manner so that each operates one part of the double brake through a separate toggle. The construction of this double brake and means for automatically taking up slack therein forms the subject-matter of Specification 440,649, [Group XXXIV]. The drum 53 is shown ribbed externally in the lower part of Fig. 1.